C13 Flashcards
What caused the oxygen levels to increase on Earth?
As plants and algae began to form in the oceans, they would make their own food through photosynthesis by using the energy from the Sun. This produced oxygen gas as well as removing carbon dioxide from the atmosphere.
The early atmosphere contained a lot of water vapor. Where did it go?
As the Earth cooled down, it condensed to form the oceans
Which process removed carbon dioxide from the atmosphere?
The formation of sedimentary rocks removed carbon dioxide from the atmosphere
Why did nitrogen build up in the atmosphere?
It is unreactive
How were crude oil and natural gas formed?
From the remains of plankton deposited in muds on the seabed.
These remains were covered sediments that became layers of rock when compressed over millions of years.
What are greenhouse gases?
Gases that directly contribute to the greenhouse effect
What are the 3 main greenhouse gases?
- Water vapor
- Methane
- Carbon dioxide
What is global warming?
The increase in the average temperature of the Earth’s atmosphere globally
Why is there an increase of greenhouse gases in the atmosphere?
- Burning fossil fuels in vehicles releases carbon dioxide
- Farming cattle releases methane
- Deforestation releases carbon dioxide
Why is global warming difficult to prove?
There are so many factors to consider and many tests can be biased
How was ammonia and methane removed?
It reacted with oxygen formed by algae and plants
CH4 + 2O2 –> CO2 + 2H2O
4NH3 + 3O2 –> 2N2 + 6H2o
What is carbon footprint?
The carbon footprint of a product, service, or event is the total amount of carbon dioxide and other greenhouse gases emitted over its full cycle.
3 consequences of rising levels of greenhouse gases
- Rising sea levels due to melting ice caps in the Arctic
- Increase in global average air temperatures
- Increasingly common extreme weather events
Why is the greenhouse effect necessary for life on Earth?
Greenhouse gases are crucial to keeping our planet at a suitable temperature for life. Without it, the Earth would be too cold for life to exist.
What actions can be taken to reduce a carbon footprint?
- Carbon taxes
- Carbon capture and storage
- Increased use of alternative energy
What are the problems of reducing the carbon footprint?
- Incomplete international cooperation
- Lack of public information and education
- Scientific disagreement over climate change
- Economic limitations
How is carbon monoxide released?
By incomplete combustion of carbon in fuel
What are the issues regarding sulfur dioixde and nitrogen oxides?
They cause respiratory problems in humans and cause acid rain which damages plants
Why is carbon monoxide harmful?
It is an odorless and colourless toxic gas that binds to haemoglobin in the blood, reducing the amount of oxygen provided to the body’s vital organs
What are the 4 main atmospheric pollutants?
Carbon monoxide, sulphur dioxide, nitrogen oxide and particulates
What is used to analyze gas levels in the Earth’s atmosphere thousands of years ago?
Ice cores which have gases trapped inside them from thousands of years ago
How is nitrogen oxide released into the atmosphere?
Through the oxidation of nitrogen in air at high temperatures in vehicle engines
Why is nitrogen oxide harmful?
The toxic gas can inflame the lining of the lungs and trigger asthma attacks
What are the advantages of complete combustion compared to incomplete combustion?
- Less soot (carbon particulates) released
- Carbon monoxide is not produced
- More energy is released
How are particulates harmful?
- Can cause cancer
- Damage cells
- Cause global dimming
How are particulates released?
When hydrocarbon molecules don’t burn completely
Where did the carbon dioxide in the early atmosphere come from?
Volcanic activity
At what temperature on Earth, would oceans have started to form?
100 degrees Celsius
How does heating limestone release carbon dioxide?
Limestone or calcium carbonate breaks down into calcium oxide and carbon dioxide when heated
Scientists do not know the accurate composition of the Earth’s early atmosphere. Suggest why.
Humans had not evolved as it was billions of years ago
Oxidation of hydrogen
Hydrogen + Oxygen —> Hydrogen Oxide (H2O) also known as water
Suggest two reasons why the world production of coal is predicted to increase
- Many countries have coal as oil is running out
- It is easy to find and extract
There is not much oxygen in the atmosphere of Mars. Suggest why.
Mars has no plants or trees
The percentage of argon in the Earth’s atmosphere today is the same as it was in the Earth’s early atmosphere. Suggest why
Argon is unreactive/inert as it is a noble gas
What colour is universal indicator in a solution of sulfur dioxide?
Red / orange / yellow, because it is an acid
When was Earth formed?
4.6 billion years ago
What % of the atmosphere is nitrogen?
78%
What % of the atmosphere is oxygen?
21%
What % of the atmosphere is carbon dioxide?
0.04%
What % of the atmosphere is argon?
0.9%
